This proposal requests funds to support travel of scientists to the seventh biannual Gordon Research Conference on Mutagenesis, at Plymouth State College, New Hampshire on July 9-13, 1990. The purpose of the Conference is to bring together leaders in the field to generate new ideas and new outlooks by providing an opportunity for interactions between these leaders. About 135 attendees are expected from universities, research institutes, industry, and government agencies all over the world. This Conference is in the even-numbered years, alternating with the Gordon Conferences on Genetic Toxicology in odd- numbered years which cover the more applied aspects of the field. In 1990, the Conference on Mutagenesis will emphasize mutagenic mechanisms. The program represents a state-of-the-art analysis of mechanisms of mutagenesis and maintenance of genetic fidelity; it places considerably greater emphasis on high resolution genetic, biochemical, and chemical approaches than past conferences. The understanding of mutagenic processes is important in assessing the genetic consequences of toxicologic agents. The recent discovery that a critical step in carcinogenesis is activation of an oncogene by mutation (either by gross DNA rearrangements or point mutations) makes the understanding of mutagenic mechanisms a particulary significant matter.